Compact modular wireless sensor

ABSTRACT

A sensor assembly includes a power source configured to store and output electrical power, a wireless communication component, a sensor, and a microprocessor electrically coupled to the power source, the wireless communication component, and the sensor. The microprocessor is configured to receive a startup command. In response to receiving the startup command, the microprocessor is configured to determine whether an amount of electrical power stored by the power source is sufficient to complete the startup command, receive the electrical power output by the power source during a first time period in response to the amount of power being sufficient to complete the startup command, and receive the electrical power output by the power source during a second time period in response to the amount of power being insufficient to complete the startup command, where the second time period is greater than the first time period.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/932,252, filed on Feb. 16, 2018, which claims priority to and thebenefit of U.S. Provisional Application Ser. No. 62/459,698, filed onFeb. 16, 2017. The contents of these applications are incorporatedherein by reference in their entireties.

FIELD

The present disclosure relates generally to sensor assemblies, and moreparticularly to wireless sensor assemblies.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Sensors are used in a wide variety of operational environments tomonitor operating and environmental characteristics. These sensors caninclude temperature, pressure, velocity, position, motion, current,voltage, and impedance sensors, by way of example. The sensors areplaced in operational environment being monitored and are designed togenerate an electrical signal or have a change in the electricalcharacteristics in response to a change in the monitored operating orenvironment characteristic. The change in the electrical characteristicsin the sensors may be a change in impedance, voltage or current.

A sensor typically includes a probe and a processing unit. The probeacquires data from the environment and transmits the data to theprocessing unit, which, in turn, determines the measurements andprovides a reading to a user. The processing unit generally requires asignificant amount of power from a power source during data processing.The power source may be an integrated battery or may be an externalpower source connected to the sensor by wires. The sensor cannot be madesmall with the integrated battery and the processing unit. When thesensor is connected to an external power source by wires, it isdifficult to use the sensor in harsh environment or to properly mountthe sensor to an apparatus with complicated structure.

Although some known processing units include low-power microprocessors,these microprocessors consume a high amount of power during startup. Insome applications where energy harvesting is important, the initialamount of power consumed at startup by the low-power microprocessors candrain an excessive amount of energy and cause a startup failure.

These issues with power consumption and harvesting, among other issueswith the operation of electronic sensors, is addressed by the presentdisclosure.

SUMMARY

The present disclosure provides a sensor assembly that includes a powersource configured to store and output electrical power, a wirelesscommunication component configured to receive electrical power from thepower source, a sensor, and a microprocessor electrically coupled to thepower source, the wireless communication component, and the sensor. Themicroprocessor is configured to receive a startup command. In responseto receiving the startup command, the microprocessor is configured todetermine whether an amount of electrical power stored by the powersource is sufficient to complete the startup command, receive anelectrical power output from the power source during a first time periodin response to the amount of electrical power being sufficient tocomplete the startup command, and receive the electrical power outputfrom the power source during a second time period in response to theamount of electrical power being insufficient to complete the startupcommand, where the second time period is greater than the first timeperiod.

In some forms, the microprocessor is configured to, in response to oneof the first time period and the second time period elapsing: obtaindata from the sensor, and transmit, using the wireless communicationcomponent, the data obtained from the sensor to an external device at agiven transmittal rate, where the given transmittal rate is based onamount of power stored in the power source.

In some forms, the given transmittal rate is based on a clock of themicroprocessor.

In some forms, the power source is a battery, and the given transmittalrate is a function of a battery life of the battery.

In some forms, receiving the electrical power output by the power sourceduring the second time period further includes receiving the electricalpower output from the power source in response to a delay time periodelapsing.

In some forms, the delay time period is controlled by at least one ofthe microprocessor and an external delay element.

In some forms, the sensor is at least one of a temperature sensor, apressure sensor, a gas sensor, and an optical sensor.

In some forms, the power source includes one of a self-powering deviceand a thermoelectric device.

In some forms, the self-powering device is a vibration device.

In some forms, the wireless communication component includes one of aBluetooth module, a WiFi module, and a LiFi module.

In some forms, the sensor further includes a housing, and the powersource, wireless communication component, and the microprocessor aredisposed within the housing.

In some forms, the housing defines a volume of less than 2 in³.

The present disclosure provides a low-power wireless sensor systemincluding a plurality of sensor assemblies. Each sensor assemblyincludes a power source configured to store and output electrical power,a wireless communication component, a sensor, and a microprocessorelectrically coupled to the power source, the wireless communicationcomponent, and the sensor. The microprocessor is configured to receive astartup command. In response to receiving the startup command, themicroprocessor is configured to determine whether an amount ofelectrical power stored by the power source is sufficient to completethe startup command, receive the electrical power output by the powersource during a first time period in response to the amount ofelectrical power being sufficient to complete the startup command, andreceive the electrical power output by the power source during a secondtime period in response to the amount of electrical power beinginsufficient to complete the startup command, where the second timeperiod is greater than the first time period. The low-power wirelesssensor system includes a wireless network operatively connecting each ofthe sensor assemblies and configured to transmit and receive databetween each of the sensor assemblies.

The present disclosure provides a method for operating a sensor assemblyhaving a power source, a wireless communication component, a sensor, anda microprocessor. The method includes determining whether an amount ofelectrical power stored by the power source is sufficient to complete astartup command. The method includes receiving the electrical power fromthe power source during a first time period in response to the amount ofelectrical power being sufficient to complete the startup command. Themethod includes receiving the electrical power from the power sourceduring a second time period in response to the amount of electricalpower being insufficient to complete the startup command, where thesecond time period is greater than the first time period.

In some forms, in response to one of the first time period and thesecond time period elapsing, the method further includes: obtaining datafrom the sensor, and transmitting, using the wireless communicationcomponent, the data obtained from the sensor to an external device at agiven transmittal rate, where the given transmittal rate is based onamount of power stored in the power source.

In some forms, the given transmittal rate is based on a clock of themicroprocessor.

In some forms, the power source is a battery, and where the giventransmittal rate is a function of a battery life of the battery.

In some forms, receiving the electrical power output by the power sourceduring the second time period further includes receiving the electricalpower output by the power source in response to a delay time periodelapsing.

In some forms, the method further includes controlling the delay timeperiod using at least one of the microprocessor and an external delayelement.

The present disclosure provides a sensor assembly including a powersource configured to store and output electrical power and a wirelesscommunication component configured to transmit data to an externaldevice and receive power from the power source, where the wirelesscommunication component has a power consumption of less than or equal to0.5 mW. The sensor assembly includes a sensor and a microprocessorelectrically coupled to the power source, the wireless communicationcomponent, and the sensor. The microprocessor is configured to receive astartup command. In response to receiving the startup command, themicroprocessor is configured to determine whether an amount ofelectrical power stored by the power source is sufficient to completethe startup command, receive the electrical power output by the powersource during a first time period in response to the amount ofelectrical power being sufficient to complete the startup command, andreceive the electrical power output by the power source during a secondtime period in response to the amount of electrical power beinginsufficient to complete the startup command, wherein the second timeperiod is greater than the first time period. The microprocessor isconfigured to, in response to one of the first time period and thesecond time period elapsing, obtain data from the sensor and transmitthe data to the external device at a given transmittal rate via thewireless communication component, wherein the given transmittal rate isbased on amount of power stored in the power source. The sensor assemblyincludes a housing defining an interior space, where the power source,wireless communication component, and the microprocessor are disposedwithin the interior space of the housing, and the housing defines avolume of less than 2 in³.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a perspective view of two wireless sensor assembliesconstructed in accordance with the present disclosure;

FIG. 2 is a schematic diagram of electronics and one form of a wirelesspower source in accordance with the teachings of the present disclosure;

FIG. 3 is another perspective view of the wireless sensor assembly ofthe first form;

FIG. 4 is another variant of a wireless sensor assembly of the firstform;

FIG. 5 is still another variant of a wireless sensor assembly of thefirst form;

FIG. 6 is another perspective view of the wireless sensor assembly ofFIG. 4;

FIG. 7 is a partial detailed view of the wireless sensor assembly of thefirst form, showing components inside the housing;

FIG. 8 is a top perspective of a lower portion of a housing of thewireless sensor assembly of the first form, with a sensor connected tothe lower portion of the housing;

FIG. 9 is a bottom perspective view of a lower portion of a housing ofthe wireless sensor assembly of the first form, with a sensor connectedto the lower portion of the housing;

FIG. 10 is a perspective view of the wireless sensor assembly of thefirst form, with an upper portion of a housing removed to showcomponents inside the housing;

FIG. 11 is a partial enlarged view of FIG. 10;

FIG. 12 is a perspective view of a wireless sensor assembly constructedin accordance with a second form of the present disclosure;

FIG. 13 is a perspective view of a wireless sensor assembly of a secondform, with an upper portion of a housing removed to show componentsinside the housing;

FIG. 14 is another perspective view of a wireless sensor assembly of asecond form, with an upper portion of a housing removed to showcomponents inside the housing;

FIG. 15 is still another perspective view of a wireless sensor assemblyof a second form, with an upper portion of a housing removed to showcomponents inside the housing;

FIG. 16 is a perspective view of a wireless sensor assembly constructedin accordance with a third form of the present disclosure;

FIG. 17 is a perspective view of a wireless sensor assembly constructedin accordance with a fourth form of the present disclosure;

FIG. 18 is a partial, cross-sectional view of a wireless sensor assemblyof the fourth form;

FIG. 19 is a perspective view of a wireless sensor assembly constructedin accordance with a fifth form of the present disclosure;

FIG. 20 is a perspective view of a wireless sensor assembly of the fifthform, with an upper portion removed to show components inside thehousing;

FIG. 21 is a perspective view of a wireless sensor assembly constructedin accordance with a sixth form of the present disclosure;

FIG. 22 is an exploded view of a wireless sensor assembly constructed inaccordance with a sixth form of the present disclosure;

FIG. 23 is a front view of the wireless sensor assembly with a capremoved to show components inside the wireless sensor assembly of thesixth form;

FIG. 24 is a perspective view of electrical and electronic componentsdisposed inside the housing of the wireless sensor assembly of the sixthform;

FIG. 25 is another perspective view of the electrical and electroniccomponents of FIG. 24; and

FIG. 26 is a bottom perspective view of the electrical and electroniccomponents of FIG. 24.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

First Form

Referring to FIG. 1, a wireless sensor assembly 10 constructed inaccordance with a first form of the present disclosure generallyincludes a housing 12 and a sensor 14. The sensor 14 may be insertedinto an aperture (not shown in FIG. 1) and connected to electrical andelectronic components inside the housing 12. Alternatively, a wirelesssensor assembly 10′ according to a variant of the first form may includea housing 12′, a sensor 14′, and wires 16′ that connect the sensor 14′to the electrical and electronic components inside the housing 12′. Thehousing 12′ may further include a pair of tabs 17′ for mounting thehousing 12′ to an adjacent mounting structure (not shown). The sensor 14or 14′ may be a temperature sensor, a pressure sensor, a gas sensor, andan optical sensor, by way of example.

Referring to FIG. 2, exemplary electronic components inside the housing12/12′, among other components, are shown in schematic form. Theelectronics 15 generally include a wireless communications component 16,which in this form is shown as a Bluetooth® RF Transmitter, and firmware17 configured to manage a rate of data transmittal from the wirelesscommunications component 16 to an external device (not shown). Thefirmware 17 resides in the microprocessor in this form. As furthershown, a power source 19 provides power to the electronics 15. The powersource 19 may take on any number of forms, including a battery asdescribed in greater detail below. In this form, the power source 19includes an “energy harvesting” configuration, which includes avibrational or thermal power generator (described in greater detailbelow), a power conditioner, and a storage component to store excessenergy.

The firmware 17 may also be configured to manage power consumed atinitial startup of the microprocessor. Low-power microprocessorstypically consume an initial large burst of power on the order of 1second or less during startup before entering true low-power mode. In anenergy harvesting application dependent on a low-power mode of themicroprocessor to function properly, the initial startup power burst mayprove insurmountable, draining the stored energy before the initialpower burst is over, causing startup failure. To address this issue ofan initial startup surge, the firmware 17 may be modified to spread outthe initial energy burst over time such that an average powerconsumption is within the capability of the energy harvestingconfiguration. Although this spreading out of energy over time willdelay startup of the microprocessor, the stored energy will not bedrained, thus inhibiting a startup failure.

In another form, additional circuitry may be added to the microprocessorto delay the output logic signal from asserting until there is enoughstored energy on the storage device such that the energy harvestingcomponents/module can get through the initial power surge. This may takethe form of an external delay element or be a part of the microprocessorwith a power conditioning chip. In one form, when there is amplevibrational or thermal energy available, startup can begin withoutspreading burst of energy, whereas with little vibrational or thermalenergy present, the energy bursts can be spread over time. In otherwords, the electronics may be configured to delay an output logic signalfrom asserting until there is sufficient stored energy to sustain aninitial power surge. These and other data management functions withinthe processor and firmware 17 are described in greater detail below.

Referring to FIG. 3, the housing 12 has opposing first and second ends18 and 20, defining a first aperture 22 (shown in FIG. 6) and a secondaperture 24, respectively. The sensor 14 has a longitudinal end insertedinto the first aperture 22 and connected to the electrical andelectronic components mounted within the housing 12. A communicationconnector 26 is disposed in the second aperture 24 and is configured toreceive a mating communication connector (not shown). The secondaperture 24 and the communication connector 26 may be configureddifferently depending on the type of the mating communication connectorto be connected. For example, the communication connector 26 may beconfigured to form a Universal Serial Bus (USB) port (FIG. 3), a USB-Cport, an Ethernet port (FIG. 4), a Controller Area Network (CAN) busport (FIG. 5) and Aspirated TIP/Ethernet port, among others. The outerprofile of the housing 12 may be configured accordingly to accommodatethe shape of the communication connector 26. The mating communicationconnector is optional and may be used to transmit raw sensing dataacquired by the sensor 14, through a network, to an external or remotedevice (not shown) for further processing. Alternatively, the rawsensing data acquired by the sensor 14 may be transmitted to theexternal device or remote device wirelessly, which will be described inmore detail below.

As further shown in FIG. 3, the housing 12 includes an upper portion 30and a lower portion 32, each of the portions defining mating wedges thataccommodate internal components and external features at opposing ends18, 20. The lower portion 32 of the housing 12 may define the firstaperture 22, whereas the upper portion 30 of the housing 12 may definethe second aperture 24, or vice versa. The mating wedges of the upperportion 30 and the lower portion 32 define a sealing interface 34 alongopposed lateral sidewalls 35. The sealing interface 34 between the upperand lower portions 30, 32 is angled so that the first aperture 22 isdefined solely by the lower portion 32 (or alternatively by the upperportion 30), rather than jointly by the upper and lower portions 30, 32.As such, sealing of the sensor 14 to the housing 12 can be maderelatively easy since the sensor 14 is sealed to only the lower portion32, as opposed to multiple pieces (i.e., both the upper portion 30 andthe lower portion 32).

Referring to FIGS. 6 and 7, the wireless sensor assembly 10 furtherincludes a mounting assembly 36 for mounting the sensor 14 to thehousing 12. The mounting assembly 36 includes a boss 38, a compressionseal 40 at a free end of the boss 38, and a nut 42. The sensor 14 isinserted through the boss 38, the compression seal 40 and the nut 42. Bysecuring the nut 42 around the boss 38 and the compression seal 40, thesensor 14 is secured and sealed to the housing 12. The nut 42 may besecured to the boss 38 via threaded connection, press-fit connection orpush-on connection. The boss 38 may be a separate component that isinserted into the first aperture 22 or may be formed as an integral partof the lower portion 32 of the housing 12.

Referring to FIG. 8, the wireless sensor assembly 10 further includes ananti-rotation mechanism 44 disposed inside the housing 12, particularlyin the lower portion 32 to prevent the sensor 14 from rotating when thesensor 14 is subjected to vibration. The anti-rotation mechanism 44includes a U-shaped seat 46 protruding from an interior surface of thelower portion 32, and an anti-rotation nut 48 disposed in the seat 46.

The wireless sensor assembly 10 further includes securing features 50for securing the lower portion 32 to the upper portion 30. The securingfeatures 50 may be screws and holes as shown in FIG. 8. Alternatively,the upper and lower portions 30 and 32 may be secured by vibrationwelding, snap-fit, or any other joining methods known in the art. Theupper and lower portions 30 and 32 may also include alignment featuresfor aligning the upper and lower portions 30 and 32 during assembly.

Referring to FIG. 9, the lower portion 32 may further include a recess51 defined in a bottom surface and a magnet 52 received in the recess51. The external magnet 52 is operable for communication with theelectrical and electronic components inside the housing 12 to disableand enable the sensor 14. The magnet 52 may be used to open a reedswitch disposed inside the housing 12 during shipping to disable thesensor 14 and preserve battery life if a battery is provided inside thehousing 12. During shipment, a small piece of adhesive tape may beplaced over the magnet 52. To make the sensor 14 operable, the adhesivetape and the magnet 52 may be removed to allow for power supply from thebattery to the sensor 14. The electrical and electronic components mayinclude a latching circuitry to prevent the sensor 14 from be disabledif it were to encounter a strong magnetic field again. In addition, therecessed area around the recess 51 may serve as a “light pipe” for anindicator LED that can be used to show the functional status of thesensor 14. The plastic housing material in this area may be made thinnerthan other parts of the housing 12 to allow the indicator LED to be seenthrough the plastic housing material.

Referring to FIGS. 10 and 11, the wireless sensor assembly 10 includeselectrical and electronic components disposed in an interior spacedefined by the housing 12 and connected to the sensor 14 and thecommunication connector 26 (shown in FIG. 3). The electrical andelectronic components may include a communication board 60, a wirelesspower source 62, a wireless communications component, firmware (notshown), and a sensor connector 66 for connecting the sensor 14 to thecommunication board 60. The communication board 60 is a printed circuitboard. The wireless power source 62, the wireless communicationscomponent, and the firmware are mounted on the communication board 60.

Signals from the sensor 14 are transmitted to the communication board 60via the sensor connector 66. As clearly shown in FIG. 11, the wires 68of the sensor 14 are directly connected to the sensor connector 66,which is mounted on the communication board 60. The wirelesscommunications component on the communications board 60 sends data tothe external device (i.e., an external processing device) for dataprocessing. The external device performs functions of data logging,computations, or re-transmitting the data to another remote device forfurther processing. The sensor 14 only collects raw data and transmitsthe raw data to the external or remote device before going to sleep. Allsensing calculations, calibration adjustments, error checking, etc., areperformed on the external or remote device so as not to use up anystored energy in the wireless power source 62 disposed within thehousing 12. As such, the battery life can be conserved.

The electrical and electronic components within the housing 12 areconfigured to receive power from the wireless power source 62 and to bein electrical communication with the sensor 14. The wirelesscommunications component has a power consumption less than about 0.5 mW.The electrical and electronic components disposed within the housing 12are powered exclusively by the wireless power source 62. The wirelesspower source 62 may be a battery or a self-powering device, amongothers. The self-powering device may be a thermoelectric device or avibration device comprising a piezo-electric device mounted to acantilevered board.

In one form, the wireless sensor assembly 10 defines a volume less thanabout 2 in³. The wireless communications component is configured totransmit raw data from the sensor 14 to an external or remote device,such as a tablet, a smartphone, a personal computer, a cloud computercenter, or any processing device that can process the data transmittedfrom the wireless communications component. The wireless communicationscomponent is selected from the group consisting of a Bluetooth module, aWiFi module, and a LiFi module. The firmware is configured to manage arate of data transmitted from the wireless communications component tothe external or remote device. The firmware controls a rate of datatransmitted from the wireless communications component as a function ofbattery life. The firmware also controls a processor clock to conservepower for the wireless power source. The firmware further monitorsstored energy in the wireless power source 62 and adjusts a rate of datatransmission from the wireless communications component as a function ofan amount of stored energy. This may be analogous to a low power mode inorder to preserve stored energy. As such, the battery life may beconserved and besides, the sensor 14 may be prevented from being turnedoff due to loss of power or at least being delayed. The rate of datatransmission may return to a predetermined normal rate until morethermal or vibration energy is available to recharge the wireless powersource 62.

Second Form

Referring to FIGS. 12 to 15, a wireless sensor assembly 110 inaccordance with a second form of the present disclosure has a structuresimilar to that of the wireless sensor assembly 10 of the first formexcept for the structure of the housing and the sensor. Like componentswill be indicated by like reference numerals and the detaileddescription thereof is omitted herein for clarity.

More specifically, the wireless sensor assembly 110 includes a housing112 and a sensor 114 (shown in FIG. 15). The housing 112 includes anupper portion 130 and a lower portion 132. The lower portion 132includes a pair of tabs 133 for mounting the housing 112 to an adjacentmounting structure. The sensor 114 is a board mount sensor. Theelectrical and electronic components received inside the housing 112include a communication board 60 and a daughter board 166 mounted on thecommunication board 60. The board mount sensor 114 is also mounted onthe daughter board 166. The daughter board 166 extends through the firstaperture 22, with one end extending outside the housing 112 and anotherend extending inside the housing 112. Signals from the sensor 114 aretransmitted to the communication board 60 via a daughter board 166. Thedaughter board 166 is supported by a pair of rubber gaskets 168. Thepair of gaskets 168 also provide a compression seal between the daughterboard 166 and the lower portion 132 of the housing 112.

Third Form

Referring to FIG. 16, a wireless sensor assembly 210 constructed inaccordance with a third form of the present disclosure generallyincludes a housing 212 having a structure similar to that of the housing12 of the first form, except that no second aperture is defined in thehousing 212 to receive a communication connector to form a communicationport. Like the wireless sensor assemblies 10 and 110 of the first andsecond forms, the wireless sensor assembly 210 includes similarelectrical and electronics components for wireless communications withan external or remote device and for transmitting the raw data from thesensor 14, 114 to the external or remote device. As such, nocommunication port is necessary.

Fourth Form

Referring to FIGS. 17 and 18, a wireless sensor assembly 310 inaccordance with a fourth form of the present disclosure includes ahousing 312 and a sensor 14 having a pair of wires 68. The housing 312includes a top housing portion 316, a heat sink structure 318, and alower base 320. The top housing portion 316 has a structure similar tothe lower portion 32 of the first form, but is attached to the heat sinkstructure 318 in an inverted fashion. An insulation layer 322 isdisposed between the heat sink structure 318 and the lower base 320. Thelower base 320 defines a pair of tabs 321 for mounting the housing 312to an adjacent mounting structure.

In this form, the wireless sensor assembly 310 does not include abattery. Instead, the electrical and electronic components inside thehousing 312 and the sensor 14 outside the housing 312 are self-powered,for example, by a thermoelectric generator (TEG) 324, which is disposedwithin the housing 312. The TEG 324, also called a Seebeck generator, isa solid state device that converts heat (temperature differences)directly into electrical energy through a phenomenon called the Seebeckeffect. The TEG 324 includes a first metallic plate 326 adjacent to theheat sink structure 318 and disposed above the insulation layer 322, anda second metallic plate 328 disposed below the insulation layer 322. Theinsulation layer 322 separates the first and second metallic plates 326and 328. Part of the heat generated from the electrical and electronicsare conducted to the first metallic plate 326 and is dissipated away bythe heat sink structure 318. Another part of the heat generated by theelectrical and electronic components inside the housing 312 is conductedto the second metallic plate 328. A temperature difference occursbetween the first and second metallic plates 326 and 328, therebygenerating electricity to power the electrical and electronic componentsinside the housing 312 and the sensor 14 outside the housing 312.

Fifth Form

Referring to FIGS. 19 and 20, a wireless sensor assembly 410 constructedin accordance with a fifth form of the present disclosure has astructure similar to that of the fourth form, differing only in theself-powering device. In this form, the self-powering device is apiezoelectric generator (PEG) 421, which converts mechanical strain intoelectric current or voltage to power the electrical and electroniccomponents inside the housing and the sensor 14 outside the housing. Thestrain can come from many different sources, such as human motion,low-frequency seismic vibrations, and acoustic noises. In the presentform, the PEG 421 includes a power transfer printed circuit board (PCB)422, a metallic plate 424, and a weight 426 attached to an end of themetallic plate 424. The metallic plate 424 functions as a cantileveredboard with the weight 426 disposed at the end to cause mechanical strainin the metallic plate 424. The mechanical strain generated in themetallic plate 424 is converted into power/electricity, which is routedto the communications board (not shown in FIG. 20) via the powertransfer PCB 422. The power transfer PCB 422 is clamped between the heatsink structure 318 and the metallic plate 424. Like the housing 312 inthe fourth form, the housing 412 of the present form includes a tophousing portion 416, a heat sink structure 418, and a lower base 420.The heat sink structure 418 in this form, however, only functions as amounting structure for the sensor 14 and the PEG 421 because heat has noeffect in generating electricity. Therefore, no insulation layer isprovided between the heat sink structure 418 and the lower base 420.

The weight 426 that is attached to the metallic plate 424 for causingmechanical strain in the metallic plate 424 may be varied and properlyselected to create a resonance in the PEG 421 at calculated frequenciesto increase the vibration and the mechanical strain in the metallicplate 424, thereby increasing the electricity being generated therefrom.

Sixth Form

Referring to FIGS. 21 to 26, a wireless sensor assembly 510 constructedin accordance with a sixth form of the present disclosure may include ahousing 512 and a sensor (not shown) that is connected to the electricaland electronic components inside the housing 512 by wires 514. Thehousing 512 has a rectangular configuration. The wireless sensorassembly 510 further includes a sensor connector 516 disposed at an endof the housing 512, and a cap 518 disposed at another end of the housing512. As in wireless sensor assembly 410 of the sixth form, the wirelesssensor assembly 510 includes electrical and electronic componentsdisposed inside the housing 512. The electrical and electroniccomponents may include a communication board 520, a self-powering devicein the form of a piezoelectric generator (PEG) 522. The PEG 522 mayinclude a metallic plate 524, and a weight 526 attached to an end of themetallic plate 524. The metallic plate 524 functions as a cantileveredboard with the weight 526 disposed at the end to cause mechanical strainin the metallic plate 524. The mechanical strain generated in themetallic plate 524 is converted into power/electricity, which is routedto the communications board 520 to power the sensor and otherelectrical/electronic components.

In any of the forms described herein, the raw sensing data acquired bythe sensors 14 can be transmitted to an external computing device, suchas a laptop, smartphone or tablet, so that processing of the raw sensingdata can occur externally. The wireless sensor assemblies have theadvantages of reducing power consumption since raw sensing data areprocessed externally. In addition, since the processing and calculationsof the data are performed on an external or remote device, a morecomplete high-resolution look-up table may be used on the external orremote device to increase accuracy, as opposed to a less accuratepolynomial curve fitting that is stored in a smaller ROM due to limitedspace available for the ROM in the sensor.

Further, the wireless sensor assemblies have the advantages of allowingfor update on the calibration curves and the look-up tables without theneed to change the circuitry of the sensors. Field replacement sensorsare assigned with identification (ID) information or code, such as anRFID tag or a barcode. During installation or replacement of thewireless sensor assembly, calibration information of the sensor 14 canbe accessed through an external device in wireless communication withthe wireless sensor assembly. By scanning or entering the IDinformation, the sensor 14 will be linked to a predetermined calibrationcurve via a network connection. In addition, the look-up table orcalibration information can be periodically updated to account fordrifts, thereby increasing measurement accuracy of the sensor 14 overthe life of the sensor 14.

In one form of the wireless sensor assemblies as disclosed herein, thedimensions of the housing are approximately 1.75 in. L×1.25 in. W×0.68in. H. When a battery is used, the housing may be larger. Due to the lowpower consumption of the Bluetooth component as the wireless component,which is less than 0.170 μW in one form of the present disclosure, thesensor 14 can be operated for at least 2 years with a selected batterywhile transmitting data every second. The low power consumption alsomakes self-powering possible. Moreover, in any of the wireless sensorassemblies described herein, the communications board can detect theamount of stored or generated energy and allow the sensor toautomatically adjust the rate of transmitting the raw sensing data basedon the amount of power available or predicted to be available.

The wireless sensor assembly according to any of the forms may be adigital sensing product that can transmit digital raw data to anexternal device or a remote device. The wireless sensor assemblyincludes interchangeable pieces to allow for easy assembly into multipleconfigurations, thus providing a “modular” construction. Each of thewireless sensor assemblies described herein can be varied to providewired or wireless connectivity, and varied mounting and sensor inputoptions.

While the wireless sensor assembly in any of the forms has beendescribed to include only one sensor 14, more than one sensors may beconnected to the electrical and electronics components inside thehousing without departing from the scope of the present disclosure. Forexample, two or more sensors 14 may be inserted into the first aperture22 and mounted by the mounting assembly 36 as shown in FIG. 6 andconnected to the communication board 60 by two sensor connectors 66.

Seventh Form

A low-power wireless sensor system constructed in accordance with aseventh form of the present disclosure may include a plurality ofwireless sensor assemblies, and a wireless network operativelyconnecting each of the wireless sensor assemblies and operable totransmit and receive data between each of the wireless sensorassemblies. The wireless sensor assemblies may be in the form of any ofthe wireless sensor assemblies described in the first to sixth forms andmay communicate among themselves or with an external device, such as atablet, a smartphone or a personal computer.

It should be noted that the disclosure is not limited to the formdescribed and illustrated as examples. A large variety of modificationshave been described and more are part of the knowledge of the personskilled in the art. These and further modifications as well as anyreplacement by technical equivalents may be added to the description andfigures, without leaving the scope of the protection of the disclosureand of the present patent.

What is claimed is:
 1. A sensor assembly comprising: a power sourceconfigured to store and output electrical power, wherein the powersource includes a self-powering device; a wireless communicationcomponent configured to receive electrical power from the power source;a sensor; and a microprocessor electrically coupled to the power sourceand communicably coupled to the wireless communication component and thesensor, wherein the microprocessor is configured to receive a startupcommand, and in response to receiving the startup command, themicroprocessor is configured to: measure an amount of electrical powerstored by the power source to determine whether the amount of electricalpower is sufficient to complete the startup command; receive anelectrical power output from the power source during a first time periodin response to the amount of electrical power being sufficient tocomplete the startup command; and receive the electrical power outputfrom the power source during a second time period in response to theamount of electrical power being insufficient to complete the startupcommand, wherein the second time period is greater than the first timeperiod.
 2. The sensor assembly of claim 1, wherein the microprocessor isconfigured to, in response to one of the first time period and thesecond time period elapsing: obtain data from the sensor; and transmit,using the wireless communication component, the data obtained from thesensor to an external device at a given transmittal rate, wherein thegiven transmittal rate is based on the amount of electrical power storedin the power source.
 3. The sensor assembly of claim 2, wherein thegiven transmittal rate is based on a clock of the microprocessor.
 4. Thesensor assembly of claim 1, wherein receiving the electrical poweroutput from the power source during the second time period furthercomprises: receiving the electrical power output from the power sourcein response to a delay time period elapsing.
 5. The sensor assembly ofclaim 4, wherein the delay time period is controlled by at least one ofthe microprocessor and an external delay element.
 6. The sensor assemblyof claim 1, wherein the sensor is at least one of a temperature sensor,a pressure sensor, a gas sensor, and an optical sensor.
 7. The sensorassembly of claim 1, wherein the self-powering device is one of athermoelectric device or a vibration device.
 8. The sensor assembly ofclaim 1, wherein the wireless communication component includes one of aBluetooth module, a WiFi module, and a LiFi module.
 9. The sensorassembly of claim 1 further comprising a housing, wherein the powersource, wireless communication component, and the microprocessor aredisposed within the housing.
 10. The sensor assembly of claim 9, whereinthe housing defines a volume of less than 2 in³.
 11. A low-powerwireless sensor system comprising: a plurality of sensor assembliesaccording to claim 1; and a wireless network operatively connecting eachof the sensor assemblies and configured to transmit and receive databetween each of the sensor assemblies.
 12. A method for operating asensor assembly having a power source, a wireless communicationcomponent, a sensor, and a microprocessor, the method comprising:measuring an amount of electrical power stored by the power source,wherein the power source includes a self-powering device; determiningwhether the amount of electrical power is sufficient to complete astartup command; receiving the electrical power from the power sourceduring a first time period in response to the amount of electrical powerbeing sufficient to complete the startup command; and receiving theelectrical power from the power source during a second time period inresponse to the amount of electrical power being insufficient tocomplete the startup command, wherein the second time period is greaterthan the first time period.
 13. The method of claim 12, wherein inresponse to one of the first time period and the second time periodelapsing, the method further comprises: obtaining data from the sensor;and transmitting the data obtained from the sensor to an external deviceat a given transmittal rate, wherein the given transmittal rate is basedon the amount of electrical power stored in the power source.
 14. Themethod of claim 13, wherein the given transmittal rate is based on aclock of the microprocessor.
 15. The method of claim 12, whereinreceiving the electrical power from the power source during the secondtime period further comprises: receiving the electrical power output bythe power source in response to a delay time period elapsing.
 16. Themethod of claim 15, further comprising controlling the delay time periodusing at least one of the microprocessor and an external delay element.17. A sensor assembly comprising: a power source configured to store andoutput electrical power, wherein the power source includes aself-powering device; a wireless communication component configured totransmit data to an external device and receive power from the powersource, wherein the wireless communication component has a powerconsumption of less than or equal to 0.5 mW; a sensor; a microprocessorelectrically coupled to the power source, the wireless communicationcomponent, and the sensor, wherein the microprocessor is configured toreceive a startup command, and in response to receiving the startupcommand, the microprocessor is configured to: measure an amount ofelectrical power stored by the power source to determine whether theamount of electrical power is sufficient to complete the startupcommand; receive the electrical power output by the power source duringa first time period in response to the amount of electrical power beingsufficient to complete the startup command; receive the electrical poweroutput by the power source during a second time period in response tothe amount of electrical power being insufficient to complete thestartup command, wherein the second time period is greater than thefirst time period; and in response to one of the first time period andthe second time period elapsing, obtain data from the sensor andtransmit the data to the external device at a given transmittal rate viathe wireless communication component, wherein the given transmittal rateis based on amount of power stored in the power source; and a housingdefining an interior space, wherein the power source, the wirelesscommunication component, and the microprocessor are disposed within theinterior space of the housing, and the housing defines a volume of lessthan 2 in³.
 18. The method of claim 12, wherein the self-powering deviceis one of a thermoelectric device or a vibration device.
 19. The sensorassembly of claim 17, wherein the self-powering device is one of athermoelectric device or a vibration device.